var i,s,n:longint;   f,g:text;

function gcd(a,b:longint):longint;
begin
if (b=0)then gcd:=a
             else gcd:=gcd(b,a mod b);
end;

function ff(x:longint):longint;
var k,j:longint;
begin
k:=0;
{if (x=3)or(x=2) then k:=0
                else} for j:=2 to x-1 do
                if gcd(j,x)>1 then k:=k+1;
                ff:=k;

end;

begin
assign(f,'fractii.in');reset(f);
assign(g,'fractii.out');rewrite(g);
read(f,n);
s:=2*n-1;
for i:=n downto 3 do
s:=s+2*(i-2-ff(i));
write(g,s);
close(f);
close(g);
end.